Occurrence of dual infection of bovine group A rotavirus in diarrhoeic calf in

Abstract

Group A bovine rotaviruses (BRVs) responsible for neonatal calf diarrhoea, have characteristic segmented genome with 11 monocistronic dsRNA segments. These segments are arranged in a pattern of 4:2:3:2 where segments 7, 8, and 9 were grouped as a triplet, typical of group A rotaviruses. However, the RNA extracted from faecal samples of 2 diarrhoeic calves showed more than 11 classical segments in silver stained gels. One of the diarrhoeic samples showed 3 additional segments whereas the other had 2 extra genomic segments in the stained gels. Thereby, suggesting the presence of more than 1 rotavirus genotype in an individual calf. The application of reverse transcription-polymerase chain reaction (RT-PCR) based G and P genotyping of rota viral RNA yielded 2 G type (G6 and G10) and 1 common P8 [11] type specific amplicon. These findings further confirmed the presence of dual infection in diarrhoeic calves. The presence of extra genomic RNA segments and detection of dual infection by RT-PCR in diarrhoeic calf has been reported probably for the first time in this part of the country. These findings suggested that multiple rotavirus genotypes were simultaneously circulating on the same farm. Continuous surveillance is essentially required for proper management and development of effective and sensitive diagnostic tools for control of infection on the animal farms.